1. Field of the Invention
This invention relates to pumping units in the oil field, and more particularly, to a toothed belt-driven power transmission which eliminates the need for a gear box in transmitting power from a power source to the walking beam of a pumping unit. The toothed belt drive transmission of this invention is characterized by multiple toothed belt sprockets which cooperate by means of a pair of toothed belts in order to effect smooth, efficient, positive and quiet transmission of power from a motive force to the walking beam of the pumping unit in order to facilitate reciprocation of the wireline bridle and ultimately, the sucker rod string. The power transmission of this invention requires no lubrication except in the conventional pillar block units where the bearings are located, and is characterized by reduced maintenance costs since the toothed belts are much less expensive to replace than conventional gears mounted in gear reducing boxes and currently used to transmit power from a drive source to the walking beam in conventional pumping units.
2. Description of the Prior Art
The pumping units used to pump oil from oil bearing strata or intervals in the oil field have been known for years. Such pumping units are typically characterized by a drive means or motive force, such as an electric motor, which cooperates with the drive pulley of single, double and even triple reduction gear units to effect pivotal motion of a generally horizontally disposed walking beam and horsehead, which in turn causes a wireline bridle attached to a string of sucker rods to reciprocate and pump oil from the strata. The gear box typically carries a pair of cranks and cooperating pitmans which are pivotally attached to the walking beam and cause the walking beam horsehead to reciprocate at a selected rate.
The conventional gear-reducing units provided in pumping units for transmission of primary drive power to the pitmans and walking beams at a controlled rate are relatively complex mechanisms generally characterized by multiple gears provided in an enclosed housing and partially immersed in a pool of up to several hundred gallons of oil for lubrication. As long as the oil is maintained at the proper level within the housing, the slow speed gear of the gear-reducing units is partially immersed in the oil and receives and disperses continuous lubrication. In most cases the lubricating oil composition in the gear-reducing unit must be carefully prescribed for any given installation. For example, for temperatures down to about 0.degree. Farenheit, An AGMA 5EP premium, mild extreme pressure lubricant, which is preferably characterized by a sulphur-phosphorous composition with rust and oxidation inhibitors and an anti-foam agent, is frequently used. If the temperature is expected to drop below 30.degree. Farenheit at the installation, An AGMA 4EP premium mild extreme pressure lubricant is generally specified. In any case, the lubricating oil level must be maintained above the low mark on the oil indicating gauge, but should not be filled above the high mark. Furthermore, at least every six months the operator must collect a sample of the oil in a glass jar and check it for possible dirt, sludge, water emulsion or other forms of contamination. Due to the complexity of the herringbone gear units, for example, if a gear breaks or the unit fails for other reasons such as lack of sufficient lubricating oil or oil of a particular composition, the pumping unit is rendered inoperative until the gear reducing unit is replaced or the defective part is replaced in the unit. Furthermore, both the high speed and the low speed gears in the gear reducer, as well as other parts in the unit are quite expensive and add to the cost of maintaining and operating the pumping unit over a period of time. Failure of gears in gear reducing units is quite common due to the lack of resistance to shock and the large load applied to the engaged teeth.
Accordingly, it is an object of this invention to provide a new and improved system for transmitting power from a drive source to the cranks, pitmans, and walking beam of both crank weighted and beam weighted pumping units, which system is simple in design, relatively inexpensive and which operates smoothly, quietly and efficiently, and therefore facilitates lower peak loads and longer sucker rod life.
Another object of this invention is to provide a new and improved power transmission pumping unit in the oil field which eliminates the need for reduction gear units and expensive gears, and requires no lubrication except on the conventional pillar block bearings, and which is characterized by four belt sprockets having multiple teeth for engagement with matching grooves in a pair of flexible, toothed belts to effect transmission of power from a drive means to the cranks, and ultimately to the walking beam of the pumping unit.
Yet another object of the invention is to provide a new and improved power transmission means for driving pumping units in the oil field which includes four belt sprockets, each of which is provided with multiple teeth and cooperating matching flexible, endless toothed belts for lubrication-free transmission of power from the drive means to the cranks of the pumping unit, which transmission is characterized by quiet, rugged, generally maintenance-free, dependable and efficient operation.
A still further object of this invention is to provide a new and improved toothed belt drive transmission for pumping units in the oil field which requires no lubrication except that necessary in conventional pillar block bearings, and which utilizes four belt sprockets provided with multiple teeth, and a pair of cooperating flexible, endless toothed belts for achieving quiet, smooth, slippage-free and efficient transmission of power from the drive unit to the crank of the pumping unit at a selected speed ratio.
Another object of the invention is to provide a simple, yet rugged and dependable toothed belt drive transmission for pumping units which combines the strength of meshing gears with the quietness of flexible, endless toothed belt drives to achieve a highly efficient mechanism for transmission of high speed input power to low speed output power at selected ratios.